The proposed study aims to address health disparities between Hispanic and non-Hispanic whites, particularly as it relates to HIV and drug use in Hispanic adolescents. This goal will be accomplished by two aims: AIM I is to develop an Internet-based version of the face-to-face Familias Unidas intervention (hereafter referred to as Internet-Based Familias Unidas); and AIM II is to evaluate the efficacy of Internet-Based Familias Unidas, relative to both face-to-face Familias Unidas and a community practice control condition, in preventing unprotected sexual behavior and drug use in a community sample of Hispanic adolescents living in Miami-Dade County. 270 Hispanic adolescents recruited from three high schools will be randomized using an urn design to one of three conditions: Internet-Based Familias Unidas, face-to-face Familias Unidas or Community Practice. Face-to-face Familias Unidas, a Hispanic-specific, family- centered intervention, has been found efficacious, relative to control conditions, in preventing adolescent unprotected sexual behavior and drug use in two randomized clinical trials (Pantin et al., 2009; Prado et al., 2007). Hierarchical Linear Modeling (HLM) will be used to test: (H1) Internet-Based Familias Unidas and face-to-face Familias Unidas will be more efficacious than Community Practice Control in preventing adolescent unprotected sexual behavior over time; (H2) Internet-Based Familias Unidas and face-to-face Familias Unidas will be more efficacious than Community Practice Control in preventing adolescent drug use over time; (H3) Internet-Based Familias Unidas will be more efficacious than face-to-face Familias Unidas in preventing adolescent unprotected sexual behavior over time; and (H4) Internet-Based Familias Unidas will be more efficacious than face-to-face Familias Unidas in preventing adolescent drug use over time. Additionally HLM will be used to determine whether (H1a) the effect of Internet-Based Familias Unidas and face-to-face Familias Unidas on adolescent unprotected sexual behavior will be partially mediated by family functioning; (H2a) the effect of Internet-Based Familias Unidas and face-to- face Familias Unidas on adolescent drug use will be partially mediated by family functioning; (H3a) the effect of Internet-Based Familias Unidas on unprotected sexual behavior will be partially mediated by participation rates; and (H4a) the effect of Internet-Based Familias Unidas on adolescent drug use will be partially mediated by participation rates.